Coil for electrical transformers



Feb. 18, 1930.. J. ROOTHAAN 1,747,953

COIL FOR ELECTRICAL TRANSFORMERS I Filed June 12, 1926 2 Sheets-Sheet 1 Feb. 18, 1930. RQOTHAAN 4,747,953

' COIL FOR ELECTRICAL KIRANSFORMERS Filed June 12, 1926 2 Sheets-Sheet 2 Cy I, "I 01 p Patented Feb. 18, 1930 UNETED STATES JAN ROOTI-IAAN, GF HAYES, ENGLAND COIL FOR ELECTRICAL TRANSFORT/IEES Application filed June 12, 1926, Serial No 115,578, and in Great Britain August 24, 1925.

In the specification of former Letters Patent No. 1,585,859 for im -novements in or relating to coils for electrical transformers, there is described a transformer coil eompris ing two adjacent sets of convolutions spaced apart by radial separators, the convolutions in each set being spaced apart by interposed dis tance pieces and held together by radial bind ers, the separators, distance pieces and binders being formed of homogeneous insulating material of the kind known commercially under the registered trade marks bakelite, formite, formalite and the like, arranged at intervals around the convolutions in such manner that the convolutions are mainly insulated from each other by air, or, when in use, by oil.

Now the present invention has reference to improvements in or modifications of the invention described and claimed in the said former specification and it has for its object to simplify and cheapen the construction of transformer coils of the kind referred to and to permit of them being readily coupled to 5 similar coils.

For this purpose, the two sets of convolutions forming each complete coil, and which may be formed of bare or slightly insulated conductor, are spaced apart b y a set of inner radial strips of insulating material with which are associated companion outer radial strips of insulating material and the convolution in each set thereof are spaced apart by radial sets of distance pieces of insulating material held in position by the correspond ing pair of inner and outer radial strips. The end portion of the outermost convolution of each set of convolutions may be anchored to the adjacent port-ion of the next inner convolution, as for example by an anchoring tube of insulating material encircling the adjacent portions of the outermost and inner convolutions and a wedge of insulating material forced between such portions of con volutions. Coils so constructed may be con nected together in series by connecting an end portion of one coil to an end port-ion of the next coil by a clamping device, or by soldering or other means. Tap leads may be taken from assembled coils by the aid of anchoring devices such as described, or from the junction between two coils.

in the accompanying illustrative drawings, Figs. 1 and 2 show respectively in side elevation and part plan, a portion of a transformer coil comprising two adjacent and connected sets of convolutions constructed according to the present invention. Figs. 3, 4 and 5 are cross sections to a larger scale of the coil, corre pending to the line IH-HL IV-IV and VV respectively of Fig. 2. Figs. 6 and 7 are respectively similar views to Figs. 1 and 2, showin how a number of coils such as the one shown in Figs. 1 and 2 can be connecteo up in series after they have been assembled around a leg of a transformer core, and how a tap lead can be connected to the assembled and connected coils. Fig. 8 is a section on the line VIIIVIII of Fig. 7. Fig. 9 is a detail view showing a modification.

The co l shown in Figs. 1 to 5 inclusive is made of a length of bare or slightly insulated conductor of any desired section, it is shown of rectangular section, which, from a central portion a. Fig. 2), is wound in opposite di- 73 rections around a former to constitute two parallel sets 01' convolutions o and c. The convolutions in set 5 are soaced apart by radial sets of distance pieces (Z of inst 7 material of the kind herein refer ed to, whicn extend into recesses e and 7 formed in the opposed surfaces of pairs or radial strip 6 and formed of similar insulating material, and the convolutions in set 0 are similarly spaced apart by distance pieces 9 that extend into recesses 7t and 2' formed in the opposed surfaces of similar pairs of radial strips 72. and 2' of insulating material. Each strip has at its inner end, a lug or projection bearing against the inner convolution of the set thereof to which it belongs, the outer end of each strip being without such a lug or projection. The strips f and k are arranged side by side. This is advantageous as the strips 0 of one coil can be arranged to fit against the strips 2' of adjacent coils. The outer end portion 6 of the outer convolution of the set 7) of convolutions is anchored to the next inner convolution 01" that set by a tube m of insulating material and a wedge 91 of similar material forced between them. The end portion 0 of the outer convolution of the set 0 of convolutions is similarly anchored to the next inner convolution of that set by a tube m and wedge m The two sets of convolutions being formed of one length of conductor are electrically connected together at their inner ends.

A number of coils constructed as described can be connected together in series, as shown in Figs. 6 and 7, by connecting the end portion 0 of the set of convolutions 0 of one coil to the outer portion 1)? of the next adjacent coil by any suitable metallic clamping device, such for exa nple as a U shaped metal clamp 1" and taper bolt 8 there being thus two yert'ical sets of clamping devices. Only one of such devices is shown in Fig. 6 in order to show the strips 6 f and h z' nore c learly. Aswillbe seen ,the coils are placed together so that the radial strips 2' of one coil are arrangedcloseto the radial strips 6 of the next coil below. v H I H v When it is desired totake one or more tappings from the assembledcoils, this can be done as indicated in dotted lines at in Fig. 7 where one suchtapping extends from a terminal a, and is, in the exampfle, con stituted byan extension of the strip conductor 0 ,ofwhich one of the sets of convolutions is formed. 7 01 the tapping may, as shownin Fig. 9, be constitutedbya,separate length .25 ,of conductor extending from the clamp rto the terminal to. The free end portion oftheupper and lower coils Z) and c of a group 0f Coils, may, as indicated at t and i be connected to other terminals ta a spec e y i l Each. anchoring tube m orm maybe ,threadedover the strip of conductor before the winding 'is started and slid along ,the conductor during coilin'g thereof until the final position isrea'ched. the end of theflast or outermost convolution being threaded through the tube and finally secured by the insertion of the wedge n or 72 between the outermost and next inner convolutions as described.

What I claim is Y r s '1. A. transformer coil comprising two adjacent sets of convolutions, of conductor spaced apart sideways and with the convolutions in each set spaced apart radially,the two sets of convolutions being electrically connected together at their inner ends and having free outer ends, and clamping means connecting the outer convolution of each set of. convolutionsfirmly to the next inner convolution of the set. v 1

2A transformer coil comprising two adjacent sets of convolutions of conductor, said .sets be ng electr cally connected togetherat theirinnerends andhaving free outer ends,

clamping means connecting the outer convolution of each set of convolutions'to the next inner convolution of the set, spaced sets of companion insulating devices at the inner and outer sides of each set of convolutions and spaced sets of insulating devices between the convolutions in each set thereof.

3. transformer coil comprising two adjaceht sets of convolutions of conductor electrically connected together as their inner ends and having free outer ends, clamping means connecting the outer convolution of each set of convolutions firmly to the next inner convolution of the set, radial strips of insulating material arranged between said two sets of convolutions, at difi'erent parts thereof, radial strips of insulating material arranged atthe outer side of the two sets of convolutions and each companion to one of the inner radial strips, distance pieces of 'insu'l atin "mate rial arranged between the convohiti'o is in each set thereof and held positionby an aujacent set of companion radialstrips. p

A'transfornier coil constituting independent unit, comprising two adjacent fiat parallel sets of convoluti'o' ns conductor spaced "apart sideways with "an air s'pa -e between them and liaviifg the convolutions in each setspaced apart radially and having air spaces between them, the two sets of eony utions beingelectrically connected together at theirinner ends and having free ou'ter and insulating means rigidly conn'e ctin'g the end portion only of the outer convolution of each set'of convolutions near its free end to the next in er'coiivjolut'ion of the "setttn'd in spaced relationship thereto, 5. A transformer'coil, co d pe nt 'nifi,' 2nii s ng W parallelsets of tionfs'of ulated c-oiiductor spaced'apart sideways with an air space between them and having the 66hvolutinn 'in e'achfset spac'ed a'part radially and having air spacesbetween them,"the tt'vo sets of convolution s be ng electrically ch11 neeted together at their inner eiid ears-on an Qthe'outer ends of thet'wo sets'beiiig' free; and insulating meansjsurienh'di the free end 'portion'only ofthe outer convolution:of e ach set of convolutions "and the next inner convolution of the set, near to the free ehdp6rtion of said outer convolution and firmly 'li-olding said two convolutions in spaced r e lationship.

p 6. A transformer coil coinprising't'wo adjacent sets of "convolutions of centimeter spaced apart sideways and having the convolutions in'each set 'spiac'd'apart radially, the inner ends ofsaid sets being connected'to- "gethe r, a tube of insulating "material siirr c 'undin'g a portion of the outer convolution 'of eachsetand a p'ortionof the'nexta'djaceiit convolution of the set and a "tlistaii'ce piece of insulating material jwithin said tube; and between the adjacent portions of the outer and next inner convolutions.

7. A transfoliner'coil comprising two atljacent sets of convolutions of conductor connected together at their inner ends, a tube of insulating material surrounding adjacent portions of the outer and next inner convolution of each set and a piece of insulating material wedged between said adjacent portions of convolutions, radially arranged pairs of insulating strips at the inner and outer sides of each set of convolutions, and radially arranged sets of distance pieces between the convolutions of each set thereof and each held in position circumferentially by a pair of said radially arranged strips of insulating material.

8. A transformer coil comprising two adjacent sets of convolutions of conductor spaced apart sideways and having the convolutions in each set spaced apart radially, the inner ends of said sets being connected together, means connecting the end portion of the outer convolution of each set of convolutions to the next inner convolution and in spaced relationship thereto, companion pairs of radial strips of insulating material arranged at the inner and outer sides of each set of convolutions and spaced apart circumferentially and radially arranged and circumferentially spaced sets of distance pieces arranged between the convolutions of each set thereof and each held in position by an adj acent pair of radial strips.

9. A transformer coil comprising two adjacent sets of convolutions of conductor spaced apart sideways and having the convolutions in each set spaced apart radially, the inner ends of said sets being connected together, means connecting the end portion of the outer convolution of each set of convolutions to the next inner convolution and in spaced relationship thereto, companion pairs of radial strips of insulating material arranged at the inner and outer sides of each set of convolutions and spaced apart circumferentially, each radial pair of strips for one 'set of convolutions being arranged adjacent to a radial pair of strips for the adjacent set of convolutions.

10. A transformer coil comprising two adjacent sets of convolutions of conductor spaced apart sideways and having the convolutions in each set spaced apart radially, the inner ends of said sets being connected together, means connecting the end portion of the outer convolution of each set of convolutions to the next inner convolution and in spaced relationship thereto, companion pairs of radial strips of insulating material arranged at the inner and outer sides of each set of convolutions and spaced apart circum ferentially, each strip of the pair having in its side next its set of convolutions, a radially extending recess closed at its inner end by a lug bearing against the inner convolution of the set and open at its outer end, and radially arranged and circumferentially spaced sets of distance pieces of insulating material between the convolutions of each set thereof, the ends of the distance pieces in each set thereof extending into the opposed recesses of an adj acent pair of companion radial strips.

11. A transformer coil comprising two adj acent sets of convolutions of conductor spaced apart sideways and with the convolution in each set spaced apart radially, said sets being connected together at their inner end, a tube of insulating material surrounding a portion of the outer convolutions of each set, and a portion of the next convolution of the set and a wedge of insulating material between the portions of convolutions surrounded by said tube, radially arranged and circumferentially spaced companion pairs of insulating strips at the inner and outer sides of each set of convolutions, each pair of strips for one set of convolutions being arranged adjacent to a pair of radial strips for the adjacent set of convolutions, and radially arranged and circumferentially spaced sets of distance pieces between the convolutions of each set thereof each held in position circumferentially by an adjacent pair of radial strips.

12. In a transformer, a plurality of coils each comprising two adjacent sets of convolutions of c-onductorspaced apart sideways and having the convolution in each set spaced apart radially, the two sets of convolutions being connected together at their inner ends and having free outer ends, and insulating means connecting the outer convolution of each set of convolutions, near to its free end, to the next inner convolution of the set and in spaced relationship thereto, and metallic clamping devices connecting the outer free end portion of each coil to adjacent free end portions of adjacent coils and whereby the adjacent coils are connected in series with one another,

13. In a transformer, a plurality of coils each comprising two adjacent sets of convolutions of conductor spaced apart sideways and having the convolution in each set thereof, spaced apart radially, the two sets of con= volutions being connected together at their inner ends and having free outer ends, a tube of insulating material surrounding adjacent portions of the outer convolution and next inner convolution of each set of convolutions near to the free end of the outer convolution and insulating material between the portions of the convolutions surrounded by the tube, and metallic connecting devices between the outer free end portions of each coil and outer free end portions of adjacent coils.

14. A transformer having a plurality of coils according to claim 13, wherein the metallic connecting devices between the outer convolutions of adjacent coils are arranged in parallel rows.

15. In a transformer, a group of coils each of May, 1926.

comprising two adj a'cent sets of 'convolutioiis of conductor spaced :apart sideways and having the convolution .in each set thereof, spaced apart radially, the inner en'ds'of the tWo sets of convolutions being connected together and the outer end of each set of convolutions being free and a tube of insulating material surrounding and clamping together adjacent portions of the outer and next inner convolution of each set of convolutions and electrical coupling device between the outer end portion of the outer convolution of one set of convolntions of tone coil and the outer "end portion of the outer convolution of a set o-f convolutions in an adj acent coil and a tapping extending from one of said coupling devices.

1 6. A transformer coil comprising two adjacent sets of 'convolutions of conductor connected together at their inner ends, radial strips of insulating material arranged at the inner side of each set of convolutions, radial strips of insulating material at the outer side of "each set "of convolutions, and each companion to one oi-said inner strips, and radial sets of distance pieces of insulating material arranged between the convolutions of each set of conv'olutions and held in position by an adjacent pair of inner and outer strips.

S'i'gned'a't liondomEn-glan-d, this 28th day JAN ROOTHAAN. 

